Build a Greenhouse

June 5, 2008 by: Josh

Getting a head start on the gardening season is quite difficult sometimes. Predicting that last frost can be kind of hard, especially with the erratic weather conditions these past few years.

A useful tool in planting one or two months before season is a greenhouse. A greenhouse can provide a great seeding bed for your early to mid season vegetables. Built correctly, a greenhouse can be used year-round for bountiful harvests.

Here in Eastern Tennessee, we decided to build a 9-month greenhouse. We used some base plans that the North Carolina Cooperative Extension Service created. Our primary use is to get our cool season vegetables started a few weeks in advance. For this, we used 6-mil clear plastic. Total on all the supplies was around $200. This was using pressure-treated wood and purchasing all the materials, rather than using scraps around the house.

Link to Plans: Greenhouse Plans

Highlights of Greenhouse Build

First step was to till the soil, where the greenhouse is going to sit. We did a 15×20 area to give extra room if needed. Depending on what type of vegetables you will be planting, you can add your fertilizers and composts to the soil at this time.

Next, we rolled out the plastic sheeting (6mil) and laid the ground of the greenhouse. We laid plastic on the bottom to keep out bugs and weeds. You can leave the bottom open if you prefer.

Building the base side walls of the greenhouse is very easy. At this point, you still have the flexibility to center the foundation in the middle of your tilled soil.

Here we tucked the floor layer of plastic to the side walls. We used a staple gun to tack the plastic to the outside of the wall.

Next, we cut and glued the pvc pieces together. You can by the pvc in 10 foot pieces or you can cut them yourself.

Next, we just laid the pvc section on top of the base of the greenhouse.

Here is the tricky part. If you have two people, this should be a piece of cake. To lift the pvc with one person, the best way is to put the corners inside and walk the rest of the legs to the inside.

Now, you go along and attach each leg to the outside wall, with the clamps.

We preferred to build the end pieces separately, then attach to the base. You will also want to attach the tops of them to the pvc. You can do this by using a thin metal plate and bending it around the pvc, attaching each side to the top board.

Next, we placed the top plastic piece on the pvc. This is best if you can do it in one piece, rather than seeming multiple pieces together. After you have the plastic on, go around and tack it to the base wall with a staple gun. Make sure it is tight.

Here is an inside picture of the greenhouse. Look at how the back wall plastic is tucked. We decided to fold rather than cut this end piece.

Here we have attached the door we made separately. We double paned the door with plastic, just in case we puncture it with anything.

This is a flap we created to keep seal the gap between the door and the framing. We made the door just a few inches shorter, for a specific reason. After the weather warms up, you can remove this flap and allow insects to come in and do their magic.

Same type of flap on the bottom of the door. We did this to seal the greenhouse as tight as possible.

Here is a picture of the greenhouse door latch.

Overall, this was a fun and exciting project to tackle. You can complete this size of greenhouse in about a day, with one person. Thanks to the North Carolina Cooperative Extension Service for their plans. Good luck with your greenhouse and remember to plan everything out before you get started!